The present invention relates to a low permeation sealing member for reducing permeation of hydrocarbons from a vessel or tank.
Fluid tanks are common in several industries. For example, fuel tanks for motorized vehicles have been used for many years. Many of the current fuel tanks installed in motorized vehicles are made of various materials through which fuel molecules permeate.
Manufacturers of fuel tanks have been challenged in reducing hydrocarbon escape, leakage and permeation from fuel tanks to the atmosphere. An interface between a tank wall and a fuel delivery module cover is one issue of hydrocarbon permeation which many fuel tank manufacturers work to reduce. One problem which fuel tank manufacturers have experienced is related to hydrocarbon fuel molecules or particles permeating through a sealing member material. As hydrocarbon molecules are permeated and/or absorbed through the sealing member material, part of the sealing member expands in size due to absorption of the hydrocarbon molecules until the hydrocarbon molecules permeate through the material. At times, this results in material cracking.
Another problem that fuel tank manufacturers have experienced is hydrocarbon xe2x80x9cmicro-leaks,xe2x80x9d wherein hydrocarbon molecules leak and escape between the surfaces of the sealing member, the fuel tank, and the fuel delivery module cover. Many sealing members are at least partially comprised of low permeation material which is relatively stiff and not durable. Typically, the properties of low permeation and sealing ability are inversely related. Thus, as a material increases its characteristic as a low permeation material, the material typically becomes more rigid and allows more micro-leaks between surfaces. In many situations, a low permeation material, when engaged with a tank wall surface, allows a considerable amount of hydrocarbon micro-leaks therebetween.
Thus manufacturers have been challenged in implementing low permeation materials in sealing members to reduce diffusion of hydrocarbons through the sealing members yet maintain durability of the sealing member to reduce hydrocarbon micro-leaks between surfaces of a vessel, the material, and a sealing assembly.
The present invention provides an improved low permeation sealing member for reducing permeation of hydrocarbons from a vessel. The low permeation sealing member is configured to reduce both hydrocarbon diffusion through material of a sealing member and reduce micro-leaks between surfaces of the sealing member, a fuel tank wall, and a sealing assembly. This is accomplished by configuring a low permeation sealing member having both low permeation material to reduce movement of hydrocarbons through the sealing member material and an elastic, durable material to aid in reducing micro-leaks.
The low permeation sealing member includes an elongated body having a contact surface and a low permeation barrier layer attached along the contact surface of the elongated elastic body. The low permeation barrier layer has opposite edges spaced apart to define a slot. The low permeation barrier layer partially covers the elongated body to allow the elongated body to expand through the slot when hydrocarbon molecules are permeated therein. The elongated elastic body provides the low permeation barrier layer with a durable, elastic property which allows the barrier layer to be compressible for radially inward forces. The low permeation barrier layer has an outer side which is configured for contacting hydrocarbon particles from the vessel to reduce permeation of hydrocarbons therefrom.